1. Field of the Invention
The invention relates to a gas turbine combustor, i.e., combustion chamber, with a premixing type burner in which for cooling purposes use is made of combinations of convective heat transfer mechanisms whose basic principle is the elimination of heat by flow.
2. Discussion of Background
Gas turbine combustion chambers of this kind, i.e., with premixing type combustion burner, are known from, for example, U.S. Pat. No. 5,193,995 which is herein incorporated by reference. The cooling air speed required for applying the above-mentioned basic principle is produced therein by a pressure drop. Because of the frictional effects in the cooling ducts, a part of the kinetic energy of the cooling medium is in principle irreversibly converted into heat and the total pressure is thereby reduced.
For good heat transfer properties of the cooling air, high speeds and therefore super-proportionally high dynamic pressures are necessary in the flow duct.
The transition from the convective cooling duct to the plenum upstream of the burners was hitherto achieved through discontinuous widening of the flow cross section, thus ejecting the fluid in an uncontrolled manner. The disadvantage of this prior art is that this entails an almost complete loss of dynamic pressure since all of the combustion air flows through the burner itself. That is, since all of the combustion air is used to cool the walls of the combustion chamber, the air flows at high speed through the cooling duct, resulting in friction induced pressure losses. This leads to a corresponding total pressure loss affecting the process. This is reflected in a lowering of the efficiency and power of the gas turbine plant.